Chinese Science Bulletin

, Volume 52, Issue 21, pp 2925–2929 | Cite as

Sinorhizobium meliloti nifA gene exerts a pleiotropic effect on nodulation through the enhanced plant defense response

  • Chen XiaoTao 
  • Zou HuaSong 
  • Yao ZhenHua 
  • Cheng HaiPing 
  • Dai XiaoMi 
  • Zhu JiaBi 
  • Yu GuanQiao Email author
Articles Microbiology


Sinorhizobium meliloti nifA gene is required for the expression of a bunch of nif and fix genes. Here, we report its pleiotropic effects on the nodule formation. Compared with wild type strain, nifA mutant significantly reduced nodule suppression rate in split-root system. The plants inoculated with mutant strain produced lower amount of daidzein and less necrotic cells on their roots. In addition, the defense genes failed to be evoked by nifA mutant at the early nodulation stage. These findings indicated that host defense response was one of the mechanisms mediated by nifA gene to regulate nodule formation during symbiosis. Even though nifA mutant could increase the number of nodules in host plant, it synthesized lower Nod factors than wild type. This suggested that nifA gene mediated multiple and diverse instances in nodulation formation.


nifA hypersensitive response nodulation Nod factor 


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Copyright information

© Science in China Press 2007

Authors and Affiliations

  • Chen XiaoTao 
    • 1
    • 2
  • Zou HuaSong 
    • 1
  • Yao ZhenHua 
    • 1
    • 2
  • Cheng HaiPing 
    • 3
  • Dai XiaoMi 
    • 1
  • Zhu JiaBi 
    • 1
  • Yu GuanQiao 
    • 1
    Email author
  1. 1.National Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological SciencesChinese Academy of SciencesShanghaiChina
  2. 2.Graduate University of Chinese Academy of SciencesBeijingChina
  3. 3.Biological Sciences Department, Lehman Collegethe City University of New YorkBronxUSA

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